Conventionally, a display device of a television apparatus, etc., is designed so that one circuit board can be used commonly for various models, for the purpose of cost reduction, etc. For example, a main board with a system microcomputer mounted thereon can possibly connect with different liquid crystal modules. Since a starting sequence can possibly differ from one liquid crystal module to another, it is necessary to switch the starting sequence on the part of the main board (system microcomputer) before a power source of the liquid crystal module is started up. Since it is possible that an input and an output of a control port are exchanged depending on the liquid crystal module, it is necessary to change the input and the output of the control port on the part of the main board before the power source of the liquid crystal module is started up.
It is also conceivable to use one main board by switching product specification. For example, to be capable of accommodating the model having a four-port video input and the model having a three-port video input, the four-port video input can possibly be pre-assembled. In such a case, it is necessary to switch the operation of the system microcomputer according to the number of ports of the video input and set an ODS (On Screen Display) display, etc.
Thus, in the case of using the circuit board including the system microcomputer commonly for various models, it is necessary to switch the operation on the part of the system microcomputer according to the starting sequence, the product specification, etc. This operation switching processing is performed when the liquid crystal module is connected to the main board in a manufacturing process or when the main board is exchanged in repairs on a customer's premise, etc. An operation switching method will be described of the system microcomputer in the conventional television apparatus with reference to FIGS. 7 and 8.
FIG. 7 is a block diagram of a main part configuration for description of the operation switching method of the system microcomputer in the conventional display device and reference numeral 100 in the drawing denotes the display device. This display device 100 is equipped with a controller 101 that outputs a timing pulse necessary for driving/displaying of a liquid crystal panel (not shown), a main board 102 that controls the operation of the display device 100, a power source unit 103 that supplies power to each component, and an inverter 104 that drives a backlight of the liquid crystal panel. The main board 102 is equipped with a connector 102a shown in FIG. 6, a system microcomputer 102b, and a memory 102c that stores various adjustment values, user setting values, etc.
FIG. 8 is a diagram of an appearance configuration of the connector 102a shown in FIG. 7. FIG. 8(A) is a diagram of the connector 102a as viewed from the top and FIG. 8(B) is a diagram of the connector 102a as viewed at an angle. To cause the system microcomputer 102b to perform different operations, the connector 102a has eight ports #1 to #8 pre-assigned thereto and by switching high/low of each port, the operation of the system microcomputer 102b is switched. Specifically, a plug 105 shown in Fig. (B) is inserted into any of the ports #1 to #8 with which the connector 102a is equipped. In this example, the plug 105 is inserted into the location of the port #6. The system microcomputer, reading bit assignment at this moment, switches the operation accordingly.
Many of the television apparatuses currently on the market pre-store multiple pieces of setting value data (e.g., sound frequency characteristic table, temperature correction table, etc.) that differ from one model to another and the system microcomputer of the television apparatus, given model identification information (e.g., model number and screen size) by the connector and the plug, can identify its own setting value data out of the multiple pieces of setting value data. The system microcomputer can switch the operation based on the identified setting value data.
In this connection, a technology is known of updating programs of firmware, etc., by use of a memory card. For example, an image forming device described in Patent Reference Document 1, equipped with a model information memory portion that memorizes model information of the device, an access portion that accesses the memory card in which various programs are pre-recorded for various different models of the device, a distinguishing portion that distinguishes the program suitable for the device out of the various programs recorded in this memory card, based on the model information of the device, and a transfer portion that transfers this distinguished program from the memory card to a program storage portion, is designed to be capable of efficiently updating the programs with simple configuration.